U.S. patent number 11,094,618 [Application Number 17/043,558] was granted by the patent office on 2021-08-17 for power switching modular element and dismountable assembly of a plurality of modular elements.
This patent grant is currently assigned to INSTITUT VEDECOM. The grantee listed for this patent is INSTITUT VEDECOM. Invention is credited to Friedbald Kiel.
United States Patent |
11,094,618 |
Kiel |
August 17, 2021 |
Power switching modular element and dismountable assembly of a
plurality of modular elements
Abstract
The invention relates to a modular element (2) comprising a
stratification of first and second electroconductive plates (PH2,
PB2) which are separated by an intermediate dielectric layer (CD2)
and at least one electronic power switching chip (CP1, CP2) which
is implanted between the first and second plates, the chip having a
upper face comprising a first power electrode and a switching
control electrode and a lower face comprising a second power
electrode, and the first and second power electrodes being in
electrical continuity respectively with the first and second
plates. According to the invention, the modular element comprises a
plurality of openings (OG2, OA2, OB2, OC2, OD2) extending into the
stratification from outer surfaces of the first and second plates
and perpendicularly to said outer surfaces, the plurality of
openings comprising at least one first opening (OG2) communicating
with the switching control electrode and at least one second
opening (OA2, OB2) passing through the entire stratification, the
first and second openings each comprising a dielectric layer (DE2)
and an electroconductive layer (CI2), and the electroconductive
layer of the first opening being electrically connected to the
switching control electrode.
Inventors: |
Kiel; Friedbald (Fontainebleau,
FR) |
Applicant: |
Name |
City |
State |
Country |
Type |
INSTITUT VEDECOM |
Versailles |
N/A |
FR |
|
|
Assignee: |
INSTITUT VEDECOM (Versailles,
FR)
|
Family
ID: |
62751080 |
Appl.
No.: |
17/043,558 |
Filed: |
March 29, 2019 |
PCT
Filed: |
March 29, 2019 |
PCT No.: |
PCT/FR2019/050736 |
371(c)(1),(2),(4) Date: |
September 29, 2020 |
PCT
Pub. No.: |
WO2019/186080 |
PCT
Pub. Date: |
October 03, 2019 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20210057315 A1 |
Feb 25, 2021 |
|
Foreign Application Priority Data
|
|
|
|
|
Mar 30, 2018 [FR] |
|
|
1852816 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L
24/33 (20130101); H01L 23/49517 (20130101); H01L
24/96 (20130101); H01L 25/117 (20130101); H01L
23/3735 (20130101); H01L 23/473 (20130101); H01L
25/072 (20130101); H01L 23/49575 (20130101); H01L
25/50 (20130101) |
Current International
Class: |
H01L
23/495 (20060101); H01L 25/07 (20060101); H01L
23/00 (20060101); H01L 23/473 (20060101); H01L
23/373 (20060101) |
Field of
Search: |
;257/676 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
International Search Report for PCT/FR2019/050736 dated Jul. 2,
2019. cited by applicant .
Written Opinion for PCT/FR2019/050736 dated Jul. 2, 2019. cited by
applicant.
|
Primary Examiner: Williams; Alexander O
Attorney, Agent or Firm: Sandberg Phoenix & von Gontard,
P C.
Claims
The invention claimed is:
1. A power switching modular element comprising a lamination of
first and second electroconductive plates that are separated by an
intermediate dielectric layer, and at least one electronic power
switching chip which is implanted between said first and second
electroconductive plates, said electronic power switching chip
having an upper face comprising a first power electrode and a
switching control electrode, and a lower face comprising a second
power electrode, and said first and second power electrodes being
electrically connected to said first and second electroconductive
plates, respectively, wherein said power switching modular element
comprises a plurality of openings which extend into said lamination
from the outside surfaces of said first and second
electroconductive plates and perpendicularly to said outside
surfaces, said plurality of openings comprising at least one first
opening that communicates with said switching control electrode,
and at least one second opening which passes through the entirety
of said lamination, said first and second openings each comprising
a dielectric layer and an electroconductive layer, and said
electroconductive layer of said first opening being electrically
connected to said switching control electrode.
2. The power switching modular element according to claim 1,
wherein said openings are distributed in a manner having a fixed
spacing pitch.
3. The power switching modular element according to claim 1,
wherein said power switching modular element comprises two
electronic power switching chips which are mounted in parallel,
said electronic power switching chips being implanted side-by-side
and having the switching control electrodes thereof facing each
other, and comprising a first opening that communicates with said
switching control electrodes and having an electroconductive layer
that is electrically connected to the switching control
electrodes.
4. The power switching modular element according to claim 1,
wherein said electronic power switching chip is a transistor chip
of the vertical type.
5. A disassemblable power switching assembly comprising at least
two power switching modular elements according to claim 1 and a
plurality of electroconductive assembly pins, wherein said
electroconductive assembly pins are received in said openings of
said power switching modular elements and ensure mechanical
assembly and electrical connection functions between said power
switching modular elements.
6. The disassemblable power switching assembly according to claim
5, wherein said two power switching modular elements are arranged
top-to-bottom.
7. The disassemblable power switching assembly according to claim
5, wherein said power switching assembly has, on an outside surface
of one of said power switching modular elements, accessibility to a
plurality of electrical connections with the switching control
electrodes of the electronic power switching chips of said power
switching modular elements, said plurality of electrical
connections being ensured by means of said first openings of said
power switching modular elements and said electroconductive
assembly pins.
8. The disassemblable power switching assembly according to claim
5, wherein said power switching assembly comprises a fluid
circulation channel defined by a space between said power switching
modular elements, said space being determined by a spacing between
said power switching modular elements obtained by means of said
electroconductive assembly pins.
9. The disassemblable power switching assembly according claim 5,
wherein said power switching assembly also comprises at least one
assembly and interconnection element that is interposed between
said power switching modular elements, said assembly and
interconnection element comprising at least one electroconductive
bar in which a plurality of through-openings are arranged, said
through-openings being distributed by said fixed spacing pitch, and
receiving said conductive assembly pins.
10. The disassemblable power switching assembly according to claim
9, wherein said assembly and interconnection element comprises at
least two electroconductive bars, said electroconductive bars being
arranged having a specified mutual spacing, so as to form a fluid
circulation channel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is the US National Stage under 35 USC .sctn. 371
of International Application No. PCT/FR2019/050736, filed 29 Mar.
2019 which claims the priority of the French application 1852816
filed on 30 Mar. 2018, the content (text, drawings and claims) of
both being incorporated herein by reference.
BACKGROUND
The invention relates in a general manner to the field of power
electronics. More particularly, the invention relates to power
switching modular elements, and to dismountable (disassemblable)
assemblies of such modular elements.
The power switching modules form the building blocks required for
constructing electronic power devices. The power switching modules
can be associated in order to form switching bridges, or associated
in parallel in order to pass the desired current. The switching
bridge branches, made up of two electronic power switches, are
elementary power modules that are very widespread for implementing
electronic power devices such as inverters and power
converters.
The present-day needs are promoting a search for increased
modularity, in particular in order to allow for different circuits
to be achieved, from the simplest to the most complex, starting
from the same modular brick, to increase standardization, and to
reduce costs. Furthermore, a more advanced modularity makes it
possible to reduce the scrap value of the production, given the
possibility of testing the functionality at the level of the
elementary bricks.
The compactness of the power switching modules is an essential
feature, not only for reducing material costs, but also for
achieving the best possible design compromises. Indeed, the
compactness promotes the reduction of resistive, inductive, and
capacitive parasitic elements. Reducing the parasitic inductances,
in particular in the power busbars, is important in order to
protect the circuits from possibly destructive overvoltages,
improve the control of the electromagnetic radiation, reduce the
heat generated, and increase the switching speed.
The compactness of the architectures is also required for judicious
use of new power semi-conductors, currently, such as, silicon
carbide (SiC) and gallium nitride (GaN) and, soon, diamond. Indeed,
the greater current densities and switching frequencies brought
about by the new power semi-conductors promote greater
compactness.
The 3D architectures are of some interest with regard to increasing
the compactness of modules and electronic power devices. However,
the cooling constraints are critical in these architectures, and
efficient solutions have to be implemented here. Extraction of the
dissipated energy as close as possible to the power chips is
necessary in order to keep the temperatures of the components below
critical values, and to guarantee thermal equilibrium. Double-face
cooling of the power chips is desirable. Cooling devices that
operate by means of a heat-transfer fluid and/or use heat-pipes may
be required.
The architectures that facilitate the implementation of SiP (System
in Package) type devices are of interest due to the benefit they
bring in terms of integration level and compactness. A power
switching module architecture which allows for flexibility in the
spatial location of electrodes is of interest for implementing SiP
devices.
The disassemblable nature of the architectures, down to the most
elementary possible brick, is a significant advantage for
reparability. The technology known as "press-pack," in which the
electrical contacts are ensured by means of mechanical pressure or
clamping means, makes it possible to achieve testable and
replaceable elementary bricks, while bringing about an improvement
in the reliability in applications having extreme thermal cycles,
by eliminating welding.
It now appears to be desirable to propose a power switching module
having a new elementary switching brick architecture which is
suitable for disassemblable assemblies of the parallel and/or
stacked type, the new SiC and GaN power semi-conductors, in
particular GaN transistors having a lateral structure, as well as
3D and "press-pack" technologies, and economical mass production
based on printed circuit production technologies.
SUMMARY
According to a first aspect, a power switching modular element
comprises a lamination of first and second electroconductive plates
which are separated by an intermediate dielectric layer, and at
least one electronic power switching chip which is implanted
between the first and second electroconductive plates, the
electronic power switching chip having an upper face comprising a
first power electrode and a switching control electrode, and a
lower face comprising a second power electrode, and the first and
second power electrodes being in electrical continuity with the
first and second electroconductive plates, respectively. The power
switching modular element comprises a plurality of openings
extending into the lamination from outer surfaces of the first and
second electroconductive plates perpendicularly to the outer
surfaces, the plurality of openings comprising at least one first
opening that communicates with the switching control electrode, and
at least one second opening that passes through the entire
lamination, the first and second openings each comprising a
dielectric layer and an electroconductive layer, and the
electroconductive layer of the first opening being electrically
connected to the switching control electrode.
According to a particular feature, the openings are distributed
having a fixed spacing pitch.
According to another particular feature, the power switching
modular element comprises two electronic power switching chips
which are mounted in parallel, the electronic power switching chips
being implanted side-by-side and having the switching control
electrodes thereof arranged facing each other, and comprising a
first opening that communicates with the switching control
electrodes and having an electroconductive layer that is
electrically connected to the switching control electrodes.
According to yet another particular feature, the electronic power
switching chip is a transistor chip of the vertical type.
It will be noted that the power switching modular element is well
suited to implementing various types of electronic mounting of
transistors, such as half-bridge, full bridge, parallel, cascade
and other types of mounting, and cascade switching bridges and
matrices.
According to another aspect, the disassemblable power switching
assembly comprises at least two power switching modular elements as
briefly described above, and a plurality of electroconductive
assembly pins, in which the electroconductive assembly pins are
inserted into the openings of the power switching modular elements
and ensure mechanical assembly and electrical connection functions
between the power switching modular elements.
According to a particular feature, the two power switching modular
elements are arranged top-to-bottom.
According to another particular feature, the disassemblable power
switching assembly has, on an outside surface of one of the power
switching modular elements, accessibility to a plurality of
electrical connections with the switching control electrodes of the
electronic power switching chips of the power switching modular
elements, the plurality of electrical connections being ensured by
means of first openings of the first power switching modular
elements and the electroconductive assembly pins.
According to yet another particular feature, the disassemblable
power switching assembly comprises a fluid circulation channel
formed by a space between the power switching modular elements, the
space being determined by a spacing between the power switching
modular elements obtained by means of electroconductive assembly
pins.
According to yet another particular feature, the disassemblable
power switching assembly also comprises at least one assembly and
interconnection element that is interposed between the power
switching modular elements, the assembly and interconnection
element comprising at least one electroconductive bar in which a
plurality of through-openings are arranged, the through-openings
being distributed by the fixed spacing pitch, and receiving the
conductive assembly pins.
According to yet another particular feature, the assembly and
interconnection element comprises at least two electroconductive
bars, the electroconductive bars being arranged having a specified
mutual spacing, so as to form a fluid circulation channel.
DESCRIPTION OF THE FIGURES
Other advantages and features of the present invention will emerge
more clearly upon reading the detailed description, below, of a
plurality of particular embodiments of the invention, with
reference to the accompanying drawings, in which:
FIG. 1 is a perspective view showing the architecture of a power
switching module according to the prior art;
FIG. 2 is a simplified cross-sectional view showing a first
embodiment of a power switching modular element;
FIG. 3 is a simplified view from below showing, in the power
switching modular element of FIG. 2, the positioning of an
interconnection opening below a grid electrode of a transistor
chip;
FIG. 4 is a simplified cross-sectional view showing a second
embodiment of a power switching modular element;
FIG. 5 is a simplified view from below showing, in the power
switching modular element of FIG. 4, the positioning of an
interconnection opening below grid electrodes of transistor
chips;
FIG. 6 is a simplified cross-sectional view showing an embodiment
of a power switching assembly, comprising a fluid circulation
channel;
FIG. 7 is a simplified cross-sectional view showing a first
embodiment of an assembly and interconnection element that can be
used for achieving power switching assemblies;
FIG. 8 is a simplified cross-sectional view showing another
embodiment of a power switching assembly, comprising assembly and
interconnection elements as shown in FIG. 7; and
FIG. 9 is a simplified cross-sectional view showing a second
embodiment of an assembly and interconnection element that can be
used for achieving power switching assemblies.
DETAILED DESCRIPTION
In the prior art, the encapsulation of the power chips for
achieving power switching modules largely makes use of a technology
derived from the technology known as IMS (insulated metal
substrate). The chip is implanted in a sandwich structure, between
two conductive copper plates. Electrolytic deposition of copper and
silver sintering techniques are used for the electrical
interconnection of the chip. Dielectrics made of epoxy-type resins,
reinforced, or not, by fiberglass, or polyimides, are used for the
electrical isolation. Laser beam cutting and drilling are
frequently used for material removal. Copper tracks and pads for
the electrical interconnection are typically obtained by means of
wet etching of a copper sheet.
Thus, as shown for example in the prior art of FIG. 1, the 3D stack
of a power switching module PM formed of a switching bridge branch
comprises transistor chips T.sub.HS and T.sub.LS, busbars +DC and
-DC, a central busbar OUT, conducive interconnection sheets
CG.sub.U and CG.sub.L, and dielectric electrical isolation layers
IS1.sub.U, IS2.sub.U and IS1.sub.L, IS2.sub.L. The busbars +DC, -DC
and OUT, and the conductive interconnection layers CG.sub.U and
CG.sub.L are made of copper, and the dielectric electrical
insulation layers IS1.sub.U, IS2.sub.U and IS1.sub.L, IS2.sub.L are
typically made of the above-mentioned materials based on epoxy
resins or polyimides.
In this case, the transistor chips T.sub.HS and T.sub.LS are of the
vertical type and comprise source electrodes and drain electrodes
(not shown) that are located on the upper and lower faces,
respectively, of the chip. The source and drain electrodes are
electrically connected to the busbars. The grid electrode G.sub.U,
G.sub.L of the transistor chip T.sub.HS, T.sub.LS is located on the
upper face of the chip. The grid electrodes G.sub.U and G.sub.L are
connected to the conductive interconnection sheets CG.sub.U and
CG.sub.L by means of conductive tracks C.sub.U and C.sub.L and are
in electrical continuity with contact terminals GP.sub.U and
GP.sub.L, respectively. The dielectric electrical insulation layer
IS1.sub.U, IS1.sub.L ensures electrical insulation between the
busbar +DC, -DC and the conductive interconnection sheet CG.sub.U,
CG.sub.L, respectively. The dielectric electrical insulation layer
IS2.sub.U, IS2.sub.L ensures electrical insulation between the
conductive interconnection sheet CG.sub.U, CG.sub.L and the central
busbar OUT, respectively.
The electrical connections of the chips T.sub.HS and T.sub.LS to
continuous supply voltages are ensured by the busbars +DC and -DC.
The control of the grid electrodes G.sub.U and G.sub.L is ensured
by the contact terminals GP.sub.U and GP.sub.L. The midpoint of the
switching branch PM is available on the central busbar OUT which is
dedicated to the alternating voltage.
As can be seen in FIG. 1, the contact terminals GP.sub.U and
GP.sub.L, for access to the grid electrodes of the chips, are
located laterally on the structure, i.e. on the edge thereof. The
location of the contact terminals GP.sub.U and GP.sub.L is often a
disadvantage. Indeed, additional connection means have to be
provided in order to bring the electrical connections as far as the
control circuit, which is typically arranged on the upper or lower
face of the structure.
With reference to FIGS. 2 and 3, in the following a first
particular embodiment 1 of a power switching modular element, as
well as an assembly of two modular elements of this kind, will be
described.
In the concept of the invention, the power switching modular
element is a standardizable component. Advantageously, the power
switching modular element is implemented using printed circuit
board (PCB) production techniques. The techniques are mastered
perfectly, and allow for low-cost production.
Thus, in order to implement the power switching modular elements,
it is possible to make use of a combination of different production
techniques, including lamination, photolithography,
electrodeposition of metal, wet etching, and others. For the
purpose of the interconnection of power chips, it is possible to
make use of transient liquid phase (TLP) welding, sintering of
metal nanoparticle powder, or diffusion welding. Laser cutting and
laser drilling are also used and, optionally, other means such as
punch die-casting for cutting isolating and copper films or
sheets.
FIG. 2 shows two standard power switching modular elements 1.sub.A
and 1.sub.B, in a pre-assembly state. The power switching modular
elements 1.sub.A and 1.sub.B are arranged top-to-bottom. Three
conductive assembly pins 2.sub.1, 2.sub.2 and 2.sub.3 are also
provided, so as to be accommodated in the openings of the power
switching modular elements 1.sub.A and 1.sub.B.
In this case, the power switching modular elements 1.sub.A, 1.sub.B
each comprise one transistor chip CP.sub.A, CP.sub.B, respectively.
Other embodiments of the modular element may comprise a plurality
of transistor chips.
In this embodiment, the transistor chip CP.sub.A, CP.sub.B, the
upper face of which is shown in FIG. 3, is of the vertical type and
comprises source electrodes S and drain electrodes (not shown)
which form power electrodes that are located on the upper and lower
faces, respectively, of the chip. The grid electrode G of the
transistor chip CP.sub.A, CP.sub.B, which forms a switching control
electrode, is located on the upper face of the chip, at the center
thereof. The transistor chip CP.sub.A, CP.sub.B is buried in the
structure, in a sandwich formation, between two upper PH.sub.A,
PH.sub.B and lower PB.sub.A, PB.sub.B conductive plates, typically
made of copper. An intermediate dielectric layer CD.sub.A, CD.sub.B
separates the upper PH.sub.A, PH.sub.B and lower PB.sub.A, PB.sub.B
conductive plates, which plates are thus electrically isolated from
one another. The transistor chip CP.sub.A, CP.sub.B is contained in
a recess arranged in the intermediate dielectric layer CD.sub.A,
CD.sub.B and comprises the upper source face and the lower drain
face thereof, which are electrically connected to the upper
PH.sub.A, PH.sub.B and lower PB.sub.A, PB.sub.B conductive plates,
respectively.
According to the invention, an opening OG1.sub.A, OG1.sub.B is
provided in the upper conductive plate PH.sub.A, PH.sub.B. The
opening OG1.sub.A, OG1.sub.B extends from the upper face of the
upper conductive plate PH.sub.A, PH.sub.B, as far as the surface of
the grid electrode G of the transistor chip CP.sub.A, CP.sub.B. The
opening OG1.sub.A, OG1.sub.B is intended for electrical connection,
via the upper conductive plate PH.sub.A, PH.sub.B, of the grid
electrode G of the transistor chip CP.sub.A, CP.sub.B. The opening
OG1.sub.A, OG1.sub.B is typically formed by means of laser
drilling, and comprises a dielectric layer DE.sub.A, DE.sub.B and
an internal conductive layer CI.sub.A, CI.sub.B. The dielectric
layer DE.sub.A, DE.sub.B electrically isolates the upper conductive
plate PH.sub.A, PH.sub.B and the internal conductive layer
CI.sub.A, CI.sub.B from one another. The internal conductive layer
CI.sub.A, CI.sub.B is typically achieved by means of copper
metallization. As can be seen in FIG. 3, the internal conductive
layer CI.sub.A, CI.sub.B is in electrical contact with the grid
electrode G. The opening OG1.sub.A, OG1.sub.B, by way of the
internal conductive layer CI.sub.A, CI.sub.B thereof, makes it
possible to bring the electrical connection to the grid electrode
as far as the upper face of the upper conductive plate PH.sub.A,
PH.sub.B.
A plurality of other openings OA1.sub.A, OA1.sub.B to OD1.sub.A,
OD1.sub.B are arranged in the power switching modular elements
1.sub.A, 1.sub.B.
As can be seen in FIG. 2, the openings OA1.sub.A, OA1.sub.B, and
OB1.sub.A, OB1.sub.B are through-openings, passing through the
upper PH.sub.A, PH.sub.B and lower PB.sub.A, PB.sub.B conductive
plates, and the intermediate dielectric layer CD.sub.A, CD.sub.B.
The dielectric DE.sub.A, DE.sub.B and internal conductive CI.sub.A,
CI.sub.B layers are present in the openings OA1.sub.A, OA1.sub.B,
and OB1.sub.A, OB1.sub.B.
The openings OC1.sub.A, OC1.sub.B and OD1.sub.A, OD1.sub.B are
simple openings, without a dielectric layer, which are formed, for
example, by drilling in the upper PH.sub.A, PH.sub.B and lower
PB.sub.A, PB.sub.B conductive plates, respectively. In the modular
element 1.sub.A, 1.sub.B, the openings OC1.sub.A, OC1.sub.B and
OD1.sub.A, OD1.sub.B are not through-openings, and are aligned on
the same axis in the conductive plates PH.sub.A, PH.sub.B and
PB.sub.A, PB.sub.B, respectively. The openings OC1.sub.A, OC1.sub.B
and OD1.sub.A, OD1.sub.B remain continuous in the thickness of the
conductive plates PH.sub.A, PH.sub.B, and PB.sub.A, PB.sub.B,
respectively, thus avoiding any risk of a short-circuit between the
upper conductive plates PH.sub.A, PH.sub.B, and PB.sub.A, PB.sub.B,
when the conductive assembly pins 2.sub.1, 2.sub.3 are accommodated
in the openings.
In a general manner, all of the openings OG1.sub.A, OG1.sub.B and
OA1.sub.A, OA1.sub.B to OD1.sub.A, OD1.sub.B are made along axes
perpendicular to the upper and lower surface planes of the upper
PH.sub.A, PH.sub.B and lower PB.sub.A, PB.sub.B conductive
plates.
As can be seen in FIG. 2, the openings OG1.sub.A, OG1.sub.B and
OA1.sub.A, OA1.sub.B to OC1.sub.A, OC1.sub.B are spaced apart by
the same spacing pitch P in the upper conductive plate PH.sub.A,
PH.sub.B in order to allow for the openings to coincide during
assembly of the modular elements, in this case the top-to-bottom
assembly of the modular elements 1.sub.A and 1.sub.B. The openings
in the lower conductive plate PB.sub.A, PB.sub.B have the same
pitch P, although the opening OG1.sub.A, OG1.sub.B is absent in
this plate, in this embodiment.
The two modular elements 1.sub.A and 1.sub.B are assembled by
bringing them together (along arrows F). The three pins 2.sub.1,
2.sub.2, and 2.sub.3 are engaged in the openings OD1.sub.A and
OA1.sub.B, OB1.sub.A, and OG1.sub.B, and OA1.sub.A and OC1.sub.B,
respectively. The pins 2.sub.1, 2.sub.2 and 2.sub.3 ensure the
mechanical assembly and the electrical connections. Thus, the grid
electrodes G of the transistor chips CP.sub.A and CP.sub.B are
accessible on the upper face of the upper plate PH.sub.A, in the
region of the openings OG1.sub.A and OB1.sub.A, respectively.
With reference to FIGS. 4, 5 and 6, a second particular embodiment
2 of a power switching modular element according to the invention,
as well as a first assembly of two modular elements of this kind,
will now be described.
As shown in FIG. 4, the power switching modular element 2 differs
from the modular element 1 essentially by the fact that it
comprises two transistor chips CP1 and CP2, also of the vertical
type, but having a different connection configuration, and by the
grid connection opening OG2.
In a manner analogous to the modular element 1, the transistor
chips CP1 and CP2 are buried, in a sandwich manner, between the two
upper PH2 and lower PB2 conductive plates, which are typically made
of copper. The intermediate dielectric layer CD2 separates the
upper PH2 and lower PB2 conductive plates, which plates are thus
electrically isolated from one another. The transistor chips CP1
and CP2 are contained in respective recesses which are arranged in
the intermediate dielectric layer CD2.
In this embodiment, the transistor chips CP1 and CP2 are mounted in
parallel, which indicates that the source, drain and grid
electrodes thereof are contacted together, in pairs.
As shown in FIG. 5, the chip CP1, CP2 comprises the source
electrode S1, S2 on the upper face thereof, and the grid electrode
G1, G2 and the drain electrode (not shown) being located on the
lower face of the chip. In the chip CP1, CP2, the grid electrode
G1, G2 is not implanted centrally, as in the case of the modular
element 1, but on an edge of the chip. The chips CP1 and CP2 are
arranged side-by-side, having the grid electrodes G1 and G2 thereof
facing each other. The source electrodes S1, S2 and the drain
electrodes (not shown) are electrically connected to the upper PH
and lower P.sub.B conductive plates, respectively. In this case,
the opening OG2 makes it possible to connect all the grid
electrodes G1 and G2 and to take the electrical connection as far
as the upper face of the upper conductive plate PH2.
As can be seen in FIG. 4, in this case the opening OG2 is a
through-opening, passing through the upper PH2 and lower PB2
conductive plates, and the intermediate dielectric layer CD2. A
dielectric layer DE2 and a conductive layer CI2 are present in the
opening OG2, and cover the opening in the upper conductive plate
PH2. As can be seen in FIG. 5, the internal conductive layer CI2 is
in electrical contact with the grid electrodes G1 and G2 of the
chips CP1 and CP2.
By way of the internal conductive layer CI2 thereof, the opening
OG2 thus makes it possible to take the electrical connection of the
grid electrodes G1 and G2 as far as the upper face of the upper
conductive plate PH2. It will be noted that the metallization of
the dielectric layer DE2, which produces the internal conductive
layer CI2, does not extend, in the opening OG2, beyond the contact
with the grid electrodes G1 and G2, such that there is no
short-circuit between the electrodes and the lower conductive plate
PB2 to which the drain electrodes are electrically connected. It
will be noted that the presence of the opening OG2 in the lower
conductive plate PB2 makes it possible, with respect to the modular
element 1, to have, in this case, an additional conductive assembly
pin, and a regular spacing (pitch P) between the pins.
The other openings OA2, OB2, OC2 and OD2 of the modular element 2
are analogous to the openings OA1, OB1, OC1 and OD1 of the modular
element, and will not be described here.
An assembly of two modular elements 2.sub.A and 2.sub.B having four
conductive assembly pins 2.sub.4 to 2.sub.7 is shown in FIG. 6. The
conductive assembly pins 2.sub.4 to 2.sub.7 are longer than the
assembly pins 2.sub.1 to 2.sub.3 used for the assembly of FIG. 2.
In this case, the greater length of the conductive assembly pins
2.sub.4 to 2.sub.7 makes it possible to form a fluid circulation
channel CAL, while maintaining a spacing between the modular
elements 2.sub.A and 2.sub.B. A circulation of a heat-transfer
fluid can thus be established through the channel CAL in order to
cool the modular elements 2.sub.A, 2.sub.B.
As shown in FIGS. 7 and 8, standard assembly and interconnection
elements BI are provided in the invention, and can be used for
achieving assemblies AS comprising a large number of modular
elements 4.sub.A, 4.sub.B, 4.sub.C, etc. According to the
invention, the modular elements 4.sub.A, 4.sub.B, 4.sub.C, etc. can
be arranged in three dimensions in order to form assemblies AS. A
plurality of assembly and interconnection elements BI.sub.A,
BI.sub.B, etc. can be used for creating the assemblies AS.
As can be seen more clearly in FIG. 7, the assembly and
interconnection elements BI are typically in the form of conductive
bars or small plates provided with conductive assembly pins. In the
embodiment of FIG. 7, the conductive bar 3 is typically made of
copper and comprises a plurality of upper 2.sub.8H to 2.sub.11H and
lower 2.sub.8B to 2.sub.11B conductive assembly pins. The
conductive assembly pins are mounted, by means of clamping, in the
openings OE of the conductive bar 3. The openings OE have a spacing
therebetween that is equal to the pitch P. In this case, the pins
are mounted in pairs in the openings OE, an upper pin and a lower
pin being inserted into the same opening OE. It will be noted that
a pin having a greater length can be used in other embodiments in
order to replace the pair of upper and lower pins in one opening
OE.
Other assembly and interconnection elements BI.sub.F, such as that
shown in FIG. 9, can be used in the assemblies AS in order to
provide channels CAN that are typically intended for circulation of
a heat-transfer or fire-retardant fluid, or for heat pipes.
In the embodiment of FIG. 9, three conductive bars 4 are stacked
and assembled mechanically by means of the pins OF. A spacing is
retained between the bars 4, so as to obtain the channels CAN.
The claimed invention is not limited to the particular embodiments
that have been described here by way of example. Depending on the
applications, a person skilled in the art could make various
amendments and variants which are within the scope of the
invention.
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